Considerations on the stereoselective synthesis of dibrominated spiro-1,3-dioxanes. Synthesis and stereochemistry of monobrominated precursors

Abstract

The synthesis and stereochemistry of monobrominated spiro-1,3-dioxanes, involved as precursors in the diastereoselective synthesis of dibrominated 1,5-dioxaspiro[5.5]undecane derivatives bearing substituents in positions 7, 8 or 9, are reported. The structural aspects are investigated by means of NMR methods and by the molecular structure of two compounds established by single-crystal X-ray diffractometry. The data are used to determine the routes followed by the bromination reactions of spiro-1,3-dioxanes and the asymmetric induction involved in the stereoselectivity of the process.